Equipment lifecycles: Wheel loaders

Perhaps no other machine in a construction fleet demands as wide a range of torque output as the wheel loader with its grunt-and-run operation. And while this used to mean inexperienced operators could waste fuel, burn up the brakes and shock load the drivetrain, the current generation of wheel loaders eliminates or reduces many of these problems with super-sophisticated electronics.

Reducing human error
“We have taken a lot of the human factors out of the lifecycle considerations,” says Rodney Skinner, the general service manager for Cashman Equipment, a Caterpillar dealer in Las Vegas. “Now the machine has a computer that’s controlling the acceleration and deceleration, the disengagement of the clutches before the brakes engage, the modulation of clutches and the horsepower of the engine to match load and carry. Before, the operator could drag the brakes or keep his foot down and burn through the torque converter. He can’t do that any more unless he overrides the auto control.”

“We’ve definitely seen an evolution,” says Mike Goche, Komatsu wheel loader product manager. “The more electronics you have, the more control you have over the machine and the longer you can make it last,” he says.

Shock loads hit the transmission hardest, but they also affect the differentials torque converter, and to a certain extent, the engine. “A good operator is a smooth operator,” Goche says, “and now you can run and gun it and the control systems are not going to allow you to damage the machine as much.”

As a result the sticker price is going up, but all the manufacturers say the component life is getting longer and performance is increasing. “While these features may have increased the initial cost of the machine, the increase in component life and machine life has been significant,” says Wayne Powell, senior manager – service and training for Kawasaki. “As an added benefit they have increased operator comfort as well.”

Goche estimates the electronic systems introduced in mid-sized Komatsu loaders in January may add as much as 20 to 30 percent to the component life of these drivetrain components as well as increase the longevity of the frame, boom arms and cylinders.

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Investing in maintenance
Maintenance and working conditions still play a crucial role in reducing the lifecycle costs of owning and operating a wheel loader. “Harsh working conditions, poor maintenance and abusive operation can reduce the life of the machine by half,” says Goche. “Most production operations are focused on these points to keep their operating costs low. If they do not focus on these points they will not be cost competitive.”

Often it’s the simple details that lead to premature component failure and increased lifecycle costs. “They leave daily and weekly maintenance up to an operator but they don’t train him,” says Skinner, “so he doesn’t know that there is a grease fitting he’s supposed to grease.” Other details get lost when moving operators to new machines. “That happens all the time,” he says. “When we sell the machine we’re not usually talking to the operator. We’re talking to the buyer or the maintenance manager and somehow it doesn’t filter down to the operator and we end up making field trips to do some training.”

Estimating usage and turnover
Given the fairly straightforward work done by wheel loaders it’s not surprising there is not a lot of variation in the total hours of usage per year and the useful economic life of these machines.

According to Dennis Neslusan, service manager at Schmidt Equipment, a Deere dealer in North Oxford, Massachusetts, general contractors average about 1,200 to 1,500 hours of use a year. Sand and gravel material producers put in about 2,000 to 2,200 hours of use per year. And while government agencies buy a lot of wheel loaders, they generally put just 500 to 700 hours per year on a wheel loader, primarily loading sand and salt for road de-icing.

“General contractors tend to keep machines up to 10 years, or 7,000 to 12,000 hours” says Neslusan. “The sand and gravel companies turn them over a little sooner because they use them as production machines.”

Another critical area to consider is making sure your wheel loader is properly speced to handle the applications it’s in. Skinner mentions load-and-carry applications as a potential source of problems. “When you fill a 10-yard bucket and travel a mile in high gear you superheat the rear end,” he says. “For load and carry applications, you have to have an oil cooler package on the differentials. If it’s just going back and forth in one spot you don’t need the oil cooler package.”

Jobsite setup can also have a dramatic effect on component life, says Skinner, especially as the equipment gets larger. “A 2-percent increase in the slope of a long haul road can reduce the life of some components by as much as 40 percent,” he says. “You have to understand that when a machine goes to a certain site the expectancy of the lifecycle is going to change depending on the application.”

Figuring out just the right time to sell a used machine is always a tricky business, and no one formula fits the needs of all contractors. Some users replace their loaders on a fixed schedule of hours or years, regardless of the component lifecycle, says Powell. Others will wait until the anticipated cost of repairs seem prohibitive or a major failure has occurred, he says.

“If a wheel loader has been well maintained, a lot of the general contractors won’t trade them in but keep them as a backup,” Neslusan says. Trade-ins are often machines that have been a headache for the owner and are coming off warranty, he says.

Top-to-bottom rebuilds
Owners of older wheel loaders who are satisfied with their machines may want to look at a complete top-to-bottom rebuild. While the popularity of these complete overhauls varies from brand to brand, the price can be attractive. Dealers charge anywhere from 40 percent to 70 percent of the cost of a comparable new machine for complete rebuilds.

Skinner explains the procedure at Cashman: “Every nut and bolt comes out, every part is taken apart, from bumper to bumper. We take it clear down to the bare frame and we usually end up sandblasting that and bringing it back up with primer and paint. And then every component is brought back the same way.” The productivity of the rebuilt machine is at least as good as that same machine new, often a little better due to improvements that have been made to individual components over the years.

Goche suggests giving your wheel loader frame, boom arms and cylinders an honest evaluation before proceeding with a top-to-bottom rebuild. If these components are strong and healthy you can get a lot of value for your money by rebuilding or replacing the mechanical components and getting a second or even third life out of the piece, he says.

And deciding on a rebuild can be as much an accounting decision for a contractor as it is a structural or mechanical consideration. “Some companies have repair budgets that exceed their replacement budgets, so it’s easy to sell them a certified rebuild,” Skinner says. “Others may have replacement budgets that exceed their repair budgets so they have to buy new.”

Component lifecycles and replace/rebuild costs
The numbers cited below have been compiled and averaged from four manufacturers and represent a variety of wheel loaders from 100 horsepower to 300 horsepower in size. The dollar and hour amounts will also vary widely depending on applications and usage and are meant only as general guidelines for discussion purposes.

Hours: 4,000 to 10,000 Replace/rebuild costs: Low $2,000; Average $3,000; High $4,000
“Some operators can grind off a set of tires in a year and a half. Others can keep them for six or seven years,” says Herb Hutnak, safety officer and training specialist for Schmidt Equipment.

Maintenance is also critical for tire longevity, says Powell. Proper ballast and air pressure reduce tire spinning – which is the fastest way to ruin a tire other than a cut or puncture. Concrete, asphalt, shot rock or trash and recycling applications are the toughest on tires. Selecting the right tire for these applications can save you a lot of money. Retreading tires, when the case is in good shape and retreading is available, can save you 30 to 40 percent of the cost of new.

Articulation joint
Hours: 7,000 to 17,000
Replace/rebuild: Low $600; Average $1,200; High $2,300

In most conditions, good maintenance will keep this component healthy for the full lifecycle of the machine. Abrasive environments however, can dramatically shorten the life of the pins and bushings in this area. “In some highly abrasive materials there is nothing you can do to get past 5,000 hours,” says Neslusan. Regardless of the soil or operating conditions, failure to adjust the articulation joint, if necessary, can lead to extensive wear and frame damage, Powell says. “If the damage is severe, the rebuild costs, including line boring, can be high.

Hours: 7,000 to 10,000
Replace/rebuild: Low $900; Average $3,000; High $7,000.

While materials play a role, operator skill and regular maintenance are the top factors in prolonging the life of a wheel loader bucket. “Most bucket screw ups happen with new operators,” says Hutnak. “You can get a bucket to last 10,000 hours if you maintain it properly. If you don’t, you can destroy one in 1,000 hours. Larger contractors will have a maintenance team focused on bucket upkeep. The smaller guys have to do it on weekends.”

Linkage pins and bushings (Z-bar and parallel)
Hours: 6,000 to 12,000
Replace/rebuild: Low $600; Average $800; High $1,200
he Z-bar design is the most common, says Powell. Rebuild costs for parallel linkage may run a bit higher. “Inadequate or improper lubrication will wreak havoc on the pins and bushings within a few hundred hours of operation,” says Powell. “If damaged seals are not replaced promptly, extensive damage will result.”

Figure on spending about $50 to $200 a hole to replace pins and bushings depending on size. If you don’t replace these when you first notice wear, you could be in for a line boring job that will double the cost.

Bucket, boom and steering cylinders
Hours: 9,000 to 12,000
Replace/rebuild: Low $800; Average $1,000; High $3,000

The cost of the cylinder depends on its size. Protect the chrome from scratches and damage, check the seals and packing regularly and keep your hydraulic oil clean and the cylinders can outlast most other components.

Hours: 8,000 to 15,000
Replace/rebuild: Low $4,500; Average $5,500; High $15,000

Past the halfway point in your engine’s life, you may want to consider a partial or “in-frame” rebuild. This involves replacing the sleeves, pistons, valves and rings, but leaves the bottom end intact. The high dollar figure cited here would be for an “out of frame” rebuild or full engine replacement.

Hours: 8,000 to 12,000
Replace/rebuild: Low $4,200; Average $8,000; High $15,000

“Clean cool oil of the proper viscosity extends the life of any transmission,” says Powell. Also check to see if your operators are using the transmission to slow the machine down, he advises. “If the brake lights never come on, expect a shorter transmission life.”

This is becoming less of a problem with the newer machines that use electronic controls to modulate shock loads between the engine, transmission and brake system.

Hours: 10,000 to 15,000
Replace/rebuild: Low $1,200; Average $6,000; High $12,000

“Differential and planetary oils have long service intervals and tend to be more work to change than some other lubricants,” Powell says, “which causes some contractors to ignore or extend change intervals.” As a result wear metals from the gears and the wet disc brakes build up in the oil. If not changed regularly the contaminates accelerate wear, generating more metal, causing more wear. New oils and improved seals can provide longer life by improving lubrication and reducing external contaminates, he says.

Planetary drives
Hours: 10,000 to 15,000
Replace/rebuild: Low $4,000; Average $6,000; High $10,000

In many of the newer loaders the differentials, planetaries and wet disc brakes are all housed in one axle enclosure. The discussion of oils above applies here and when rebuilding one component in these systems it can be advantageous to inspect and, if necessary, rebuild or replace the other components.

Hours: 5,000 to 15,000 hours
Replace/rebuild: Low $900; Average $1,300; High: $2,000.

Few components’ lives are as affected by operator use and duty cycle as the brakes, says Powell. Riding the brakes, ramps, slopes and short duty cycles will shorten the brake life more than oil or other maintenance procedures. However, today’s wet disc brakes provide a service life unheard of 20 years ago. Brakes exceeding 15,000 hours before replacement are not uncommon.

Neslusan concurs. “Inboard wet disk brakes are just about bulletproof,” he says. “With inboard it’s not unusual to see a machine come in with 10,000 to 15,000 hours on it and never have had the axles, differentials or brakes touched. And if you look inside they still don’t need anything done.”

Hydraulic pump
Hours: 8,000 to 20,000
Replace/rebuild: Low $300; Average $2,000; High: $5,000.

The price for pump replacement depends on its size and type. The simpler design of gear pumps makes them less expensive to rebuild or replace than piston pumps and they tend to tolerate poor maintenance better too, Powell says. Keeping the correct oil clean and cool will extend any pump’s life and reduce the rebuild cost.

Cooling system/fans
Hours: 10,000 to 16,000
Replace/rebuild: Low $600; Average $5,000; High $8,000.

Periodic cleaning of the cooling system and replacement of hoses and belts reduces engine wear or damage. And at some point the coolers and radiator will require flushing and professional cooling, Powell says, especially if the loader is in a high trash environment like land clearing, agriculture or waste handling.

Sand can reduce the life of radiators that are not protected by a sand screen. Hydraulically driven fans and reversible fans make it easier to clean radiators and reduce fuel consumption and maintenance.

Hours: 10,000 to 20,000
Replace/rebuild: Low $2,500; Average $3,000; High $4,000

Repainting a wheel loader can be an extensive job, including sanding, primer, spraying several coats of paint and applying new decals. But if you plan to keep the machine the payback is more than good looks. “Funny thing about paint,” Hutnak says. “If the machine looks good, the operator takes better care of it.”